At what has been dubbed a "make or break" meeting of the World Trade Organization (WTO) in Bali this week, Indonesia's Trade Minister told CNBC there was a less than 50 percent chance of a global trade deal.

The long-anticipated deal has been in discussion since the group was first formed in 1995, and has been touted as having the potential of adding $1 trillion to the global economy by opening up international trade relations. However, political battles between member nations have hindered progress, though hopes were high that this week's meeting could lead to a breakthrough.

Asked what the chances were of closing a deal at the summit, Indonesia's Trade Minister Gita Wirjawan told CNBC: "We are cautiously optimistic...It's probably in the high 40s [in terms of percentage points] and depending on how things go today, tomorrow and the day after, hopefully that number will creep up."

Wirjawan told CNBC members had made progress in a number of other areas, however, particularly in regards to the least developed countries (LDCs) and on trade facilitation, but disputes over agriculture subsidy rules remained a sticking point.

"This [the lack of resolution on agriculture] relates to a politically centric issue that will require the kind of political will that has been talked about for a long time. In the absence of that we all understand that it's not going to be very good," he added.